This invention relates to techniques and apparatus for selectively excluding certain birds from a feeder while permitting other species to utilize the feeder.
There are prior art apparatuses which permit certain birds to use a feeder while others are excluded. One prior art type of such feeder utilizes selective size holes or the like to exclude larger birds. This prior art type of excluder has the disadvantage of admitting all small birds and excluding all large birds rather than admitting some species and excluding other species, although it is often desirable to permit a species to utilize the feeder without regard to size while excluding others, such as for example excluding full grown adults while permitting young immature House Sparrows to use the feeder.
It is also known from published studies that some species of birds will not fly under elongated wires. This technique has been utilized over fruit fields to exclude certain birds from feeding on the fruit.
These prior art excluders have not been applied to feeders, nor has a practical embodiment been developed useful for small backyard feeders to selectively permit certain species to use the feeders while excluding others, such as for example House Sparrows (Passer domesticus).